mount_smbfs problem after upgrade Samba 3.4 -> 3.5

[Per olof Ljungmark]

Hi,

I'm doing a major overhaul of our Samba servers including an upgrade to 
the latest port version, 3.5.6. I'm getting most things in place but a 
remaining problem is that I cannot any longer use mount_smbfs:

mount_smbfs -I 192.168.1.8 //peo at mars/inter /home/mnt
Password:
mount_smbfs: unable to open connection: syserr = Authentication error

Samba server log says:
mbd/sesssetup.c:1703(reply_sesssetup_and_X)
   reply_sesssetup_and_X:  Attempted encrypted session setup without 
negprot denied!


smbclient works fine and so does connecting to the shares from Windows 
and Konqerour like "smb://192.168.1.8/".

Anybody on the list with enough knowledge of Samba that could take a 
shot at this? Apparently something changed between version 3.4 and 3.5 
of Samba.

Thanks!